Microblog is a platform people can express their thoughts and municate with each other by sending posts.
A. which
B. where
C. what
D. when
网友回答
A. which
(答案→)B. where
C. what
D. when
解析：
试题分析:考查定语从句。根据结构可知platform后是定语从句，从句句意完整，判断用关系副词，而先行词是表地点的抽象名词，由此可知B选项正确。句意：微博是一个平台，在这里人们可以通过发帖来表达思想，彼此进行交流。